1. Technical Field
One or more embodiments of the invention relate to methods and apparatus for recovering sulfur from an acid gas.
2. Description of Related Art
A variety of industrial processes, such as natural gas processing, oil refining, and coal gasification, can produce acid gases that contain carbon dioxide and hydrogen sulfide, as well as other sulfur compounds, such as carbonyl sulfide and/or mercaptans. Such acid gases may be treated to recover valuable sulfur contained therein and to reduce sulfur emissions to the atmosphere. For instance, an acid gas can undergo an enrichment process where the hydrogen sulfide in the acid gas is concentrated and then treated in a Claus sulfur recovery unit. Claus sulfur recovery processes treat such enriched streams to convert hydrogen sulfide into recoverable sulfur while producing an off-gas that is suitable for incineration before venting to the atmosphere. While advances have been made in the art of sulfur recovery from acid gases, improvements are still needed, particularly for lean acid gases.